Diamond's book aims at answering the question: "Why did history unfold
differently in different continents?"
Why were the Europeans the ones who subjugated most of the world, and not
the aboriginal Australians or the Africans? The immediate answer is that
it was Eurasia that developed the most sophisticated civilizations, but
(assuming that this is true) that
begs another question: why was it Eurasia that
developed the most sophisticated civilizations?
I will say upfront that the book overall gives an intriguing
answer: the environment determined the difference.
According to Diamond,
the environment triggered differences in food production, and that triggered
pretty much everything else.
(Of course, Ellsworth Huntington had already advanced an environment-centered
theory a century earlier. Similar theories had already been discussed centuries
earlier by Montesquieu and even Aristotle. But they focused on climate, not
on environment. Karl Ritter had focused on the topography of the environment.
Basically, Diamond puts the two together: climate and topography).
The two main objections to his thesis are simple. First, some scholars disagree with the premise itself. Robert Wright (see my review) claims that history developed the same way everywhere, following the exact same pattern in every place on Earth. According to him, it is just an illusion that Western civilization and Chinese civilization are different: look close and they are identical. I will let them debate among themselves who is right.
Second (and this is my own objection), Diamond is a bit too quick to dispose of the human brain. His whole book is founded on the premise that, ultimately, our brains are all identical (or, at least, that brains differ in ways that have no effect on the development of civilization). As a cognitive scientist, I beg to disagree. I think that our brains are very different from each other, and in ways that can make a huge difference on the rest of humankind. Without Einstein's brain, I doubt that today we would have Relativity Theory. I suspect that we would have something very different. His brain, not only his environment, made a huge difference. Diamond wants me to believe that Western civilization would have been the same without Homer, Aristotle, Alexander, Newton and Darwin. I don't think so. I think it took all those brains too, and in the exact sequence, not only the environment. Otherwise, at each step in the development of Western civilization, something would have been slightly different, and all those slight differences combined over the centuries would have created a very different Western civilization. If one could take Galileo, Newton and Einstein and have them grow up in China instead of Pisa, Cambridge and Zurich, I suspect that Europe and China would be very different from what they are today. (Part of the problem may be that Westerners always think of their own geniuses as superior to Eastern geniuses: China had its own geniuses too, that shaped Chinese civilization like Newton shaped ours). And one doesn't need to consider geniuses only. A neighbor who purchases something for her house is enough to cause the entire neighborhood to change. I think the brain of that neighbor is as important as the "environment" in having changed the neighborhood. There is, after all, a reason if humans built civilizations and chimpanzees didn't, no matter how many millions of years of time they had at their disposal; and the reason is not just the environment.
That said, Diamond makes a convincing point that the environment played a very important role. (He is not convincing at all when he uses the backward civilizations of Polynesia to explain what happened to the advanced civlizations of Eurasia, but overall I find him convincing enough).
A favorable environment prompts humans to start food production (domestication of animals and agriculture). And the rest of history. THe rise of food production seems to coincide with the birth of writing, and the site where it occurs seems to be the site where food production first began within the region. And of course it coincides with the rise of urban life, and of organized states, etc. (Also, alas, of massive warfare).
Diamond probably over-rates the importance of writing. He claims that the Spaniards, led by Pizarro, defeated the Incas, ultimately, because they knew how to write and the Incas didn't. Very few people in Europe knew how to read and write, so whatever books were published they benefited only a small minority of Europeans. Last but not least, Pizarro himself was illiterate (and I suspect all of his men were too). I suspect there is a simpler reason to explain how a bunch of illiterate Europeans destroyed the mighty Inca empire: no Inca had ever been in Europe, thus they didn't know what to expect. When Europeans met with illiterate "barbarians" who were familiar with Europeans (such as the Goths or the Arabs), the Europeans fared much worse. It is not about writing, but about knowing your enemy.
Anyway, his analysis of how food production developed and spread is worth the price of the book. In Mesopotamia, several cereals and legumes were domesticated about 8,000 BC (easy to grow and store), fruit trees and nut trees that can be planted as cuttings were domesticated about 2,000 BC (they take time to become productive), fruit trees that required grafting (such as apples, pears, plums and cherries) were domesticated in the first millennium BC. I had never seen before such a detailed analysis of the development of food production.
He then argues that each continent has an axis, and that the African and American axes are obviously vertical, while the Eurasian axis is horizontal. As ideas spread, they have to spread horizontally. The advantage of the latter for the domestication of animals and plants is that the experiments carried out in one place can be easily replicated in another place: the climate is relatively stable as one moves horizontally (but varies wildly as one moves vertically). Thus food production spread more easily in Eurasia than in other continents.
Eurasia also had the advantage of having the most candidate species for domestication of wild mammals. Wild animals that can be domesticated are those that make it easy to be domesticated. Factors that matters are diet, growth rate, mating habits, social behavior, etc. Eurasia just happened to have the highest number of such "domesticable" species available in the first place.
Thus domestication and food production had an easier time to spread through Eurasia. Presumably, technology and other ideas simply followed the routes of domestication.
At the same time, humans contributed to shape the environment. Diamond shows how big mammals disappeared in several regions of the world at the time when humans colonized those regions (those animals were probably not genetically programmed to fight the new intruder).
The domestication of animals also made Euroasian people immune to many germs: by infecting domesticating humans with the germs of domesticated animals, it worked as a Darwinian laboratory. The humans who survived those new diseases became genetically "stronger" than the other humans. Any contact between these food-producing communities and the more primitive communities would result in extermination of the latter by a kind of biological weapon: germs carried by immunized humans. Witness how the Spaniards decimated the native populations of the Americas.
He is puzzled by the failure of food production to appear in areas that were obviously blessed with the right soil and the right weather, while areas with much worse soil and weather prospered. One problem, of course, is that he compares regions as they are in the 20th century. Mesopotamia was not a desert when civilization was born.
The second half of the book is devoted to analyzing how each continent developed the way it developed, and why Europeans ended up beating everybody else. He shows that it was, mostly, an "accident of geography".
For each continent he, basically, gives a speech: it is not quite the "scientific" kind of historiography that he has in mind (the one he envisions in the last chapter). One could focus on other factors and come up with the opposite story. Historiography has not reached the point that it can claim to be a science, and Diamond's erudite and articulate chapters are evidence of this. So at the end it is still all about feelings. And in this case one has the feeling that Diamond has a lot of good points. But his story is rarely "completely" convincing. For example, he emphasizes that China remained a huge empire throughout history because of its smooth coastline, and he contrasts that with the difficult coastline of Europe (that was never totally unified). But one can easily object that the smooth coastline of China should have made China easier to conquer by foreigners (and in fact China was indeed easily invaded by the Japanese and the Europeans the first time they tried). The hinterland of China is far more mountainous than Diamond seems to realize. Furthermore, China has deserts and huge rivers that Western Europe cannot even imagine. Geographically speaking, it is debatable if the Chinese topography is more or less suited than the European topography to universal empires. On the other hand, anyone with a superficial knowledge of agriculture can easily notice that there is a natural border between the fertile land of China and the dry steppes to the East. That "ecological" border might have played a bigger role than the "geographical" border. After all, it is easier to climb a mountain or cross a river than to grow enough crops in the steppes to feed an entire tribe every day of the year. The need of the Chinese agriculture to protect itself against the nomads of the East might explain the persistence of a large empire in China's territory.
Diamond's story is probably not the whole story. I still think that the "cultural mindset" matters: some groups of people may develop a keener interest in technological innovation, astronomical observation, philosophical speculation, economic activity or whatever (i.e., building civilizations) than other people. Such a mindset was probably due to a few individuals having started a trend. Similarly, rock'n'roll was born in one of the many areas where it could have been born: it was born where it was born because the people there had developed the mindset to start a new kind of music, and that mindset came from a few individuals who started selling black music to white people. That mindset ultimately comes (also) from genes. Diamond has written a politically correct book and from the outset he declared that genes have nothing to do with the development of civilizations. I suspect that many generations from now, when racism will not be an issue anymore, scientists will show that there are indeed genes that account for science, poetry, music and philosophy, just like there are genes for blue eyes and dark skin. Some individuals (and therefore the groups they belonged to) were genetically more likely to develop civilizations. Out of those groups a handful were selected by the environment (or viceversa), and here indeed the Eurasian environments may have been a big factor, as Diamond (not a geneticist) convincingly shows in this book.
Last but not least, we live in the age in which we want a mathematical demonstration for every accident of history, but one should always remember that "chance" plays a big role in each invention. If one chains together all the inventions that arose "by chance", one ends up with a major factor for a civilization to evolve the way it evolved. I suspect that many of the early human inventions came by accident. Diamond seems to think that they would have been invented anyway at approximately the same time by approximately the same people. I suspect not. I suspect that the world would be significantly different today.